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    Providing Reliability for Transactional Mobile Agents
    (Vincent Guyot, 2013) Zeghache, Linda; Hurfin, Michel; Moise, Izabela; Badache, Nadjib
    A transactional agent is a mobile agent that migrates from a site to another one in order to execute a distributed transaction assigned by a user. Works on transactional mobile agents have identified two prob- lems that can not be solved by the agent alone. The first one is related to the reliability. The lack of a fault tolerant infrastructure and method- ologies that address fault tolerant execution of mobile agents highlights a major drawback of this technology. The second problem for which the agent needs assistance is related to the atomic validation of the transac- tion. In this paper we address the mobile agent fault tolerance and the transactional support
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    Special Issue on Interconnections of Wireless Sensor Networks
    (InderScience, 2011-05) Derhab, Abdelouahid; Djenouri, Djamel; Jianguo, Ding
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    An Architectural Model for a Mobile Agents System Interoperability
    (Springer, 2007) Zeghache, Linda; Badache, Nadjib; El Maouhab, Aouaouche
    An important goal in mobile agent technology is interoperability between various agent systems. A way of achieving this goal would be to envisage a standard to be imposed on these various “agents systems” in order to allow the inter-working of various architectures of mobile agents. During the past years, different scientific communities proposed to different standardization actions, such as the Foundation for Physical Intelligent Agents (FIPA) and the Object Management Group’s MASIF (Mobile Agent System Interoperability Facilities). Although, they finally share some major targets, the OMG and FIPA current results show their distinct origins, particularly for interoperability between or within distributed systems. In this paper, we first analyze the similarities and differences, advantages and disadvantages of the Object Management Group (OMG) mobile agent and the Foundations for Intelligent Physical Agents (FIPA) intelligent agent approaches. Based on this analysis, we try to integrate these two standards to propose an architectural model for mobile agents system interoperability
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    An Ω-Based Leader Election Algorithm for Mobile Ad Hoc Networks
    (Springer Berlin Heidelberg, 2012) Melit, Leila; Badache, Nadjib
    Leader election is a fundamental control problem in both wired and wireless systems. The classical statement of the leader election problem in distributed systems is to eventually elect a unique leader from a fixed set of nodes. However, in MANETS, many complications may arise due to frequent and unpredictable topological changes. This paper presents a leader election algorithm based on the omega failures detector, where inter-node communication is allowed only among the neighboring nodes along with proofs of correctness. This algorithm ensures that every connected component of the mobile ad hoc network will eventually elect a unique leader, which is the node of the highest priority value from among all nodes within that connected component. The algorithm can tolerate intermittent failures, such as link failures, network partitions, and merging of connected network components.
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    Semantic Annotations and Context Reasoning to Enhance Knowledge Reuse in e-Learning
    (Springer Berlin Heidelberg, 2013) Boudebza, Souad; Berkani, Lamia; Azouaou, Faiçal; Nouali, Omar
    We address in this paper the need of improving knowledge reusability within online Communities of Practice of E-learning (CoPEs). Our approach is based on contextual semantic annotations. An ontological-based contextual semantic annotation model is presented. The model serves as the basis for implementing a context aware annotation system called “CoPEAnnot”. Ontological and rule-based context reasoning contribute to improving knowledge reuse by adapting CoPEAnnot’s search results, navigation and recommendation.The proposal has been experimented within a community of learners.
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    SQUIRREL: Self-Organizing Qos-roUting for IntRa-flow Contention in Ad-Hoc wiRELess Networks
    (Springer Berlin Heidelberg, 2008) Derhab, Abdelouahid
    In this paper, we use the self-organizing paradigms presented in [1] to design a new QoS-routing intra-flow contention-based protocol for wireless ad-hoc networks, called SQUIRREL. The admission control component of SQUIRREL, called: Scalable and Accurate Admission control (SAICAC), has two variants: SAICAC-Power and SAICAC-CS. SAICAC-Power estimates channel bandwidth availability through high power transmissions and SAICAC-CS through passive monitoring of the channel. Contrary to the existing intra-flow contention-based protocols, SQUIRREL can ensure all the properties of a self-organizing system and can achieve the best results in terms of of message overhead, delay, and scalability.
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    ELS: Energy-Aware Some-for-Some Location Service for Ad Hoc Mobile Networks
    (Springer Berlin Heidelberg, 2006) Derhab, Abdelouahid; Badache, Nadjib; Tari, Karim; Sami, Sihem
    In this paper, we propose a new location service for Ad hoc mobile networks. The network area is divided into non-overlapping zones. Using a hash function, a node identifier is mapped to a set of zones, in which the location information of the node are stored. We also propose a location information distribution scheme that achieves low rate of outdated location information. Using cross-layer design, the service can tolerate servers mobility and failure, and last for a long time period. Simulation Results show that the proposed location service experiences low overhead and high location information availability and accuracy.
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    Low-Cost and Accurate Intra-flow Contention-Based Admission Control for IEEE 802.11 Ad Hoc Networks
    (Springer Berlin Heidelberg, 2008) Derhab, Abdelouahid
    In this paper, we propose a new admission control method for IEEE 802.11 ad hoc networks, called Low-cost and Accurate Admission control (LAAC). The proposed method has two variants: LAAC-Power and LAAC-CS. LAAC-Power estimates channel bandwidth availability through high power transmissions and LAAC-CS through passive monitoring of the channel. Due to the shared nature of the wireless medium, contention occurs among the nodes along a multi-hop path, which leads to intra-flow contention. LAAC accurately estimates the intra-flow contention. In addition, an analytical study demonstrates that LAAC achieves optimal results in terms of overhead and delay compared to the existing intra-flow contention-based admission control methods. LAAC also utilizes two criteria for accepting flows: one during the route request phase and the other during the route reply phase, which helps to reduce message overhead and avoid flooding route requests in hot spots. Simulation results show that LAAC-CS outperforms LAAC-Power in terms of packet delivery ratio, throughput, message overhead, and energy consumption.
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    A Formal Approach for a Self Organizing Protocol Inspired by Bacteria Colonies: Production System Application
    (Springer Berlin Heidelberg, 2010) Mellah, Hakima; Hassas, Salima; Drias, Habiba; Raiah, A.; Tiguemoumine, A.
    Any dysfunction in production system (PS) is likely to be very expensive; so modelling by Multi Agent Systems (MAS) makes the production system (PS) possible to have aspects of robustness, reactivity and flexibility, which allow the PS control to be powerful and to react to all the risks being able to occur. In order to have a fault-tolerant PS, we propose when and how to recourse to a self organizing protocol making the MAS capable of changing its communication structure or organization, and thus reorganizing itself without any external intervention.
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    Tags Weighting Based on User Profile
    (Springer Berlin Heidelberg, 2011) Kichou, Saida; Mellah, Hakima; Amghar, Youssef; Dahak, Fouad
    The ’Collaborative Tagging’ is gaining popularity on Web 2.0, this new generation of Web which makes user reader/writer. The ’Tagging’ is a mean for users to express themselves freely through additions of label called ’Tags’ to shared resources. One of the problems encountered in current tagging systems is to define the most appropriate tag for a resource. Tags are typically listed in order of popularity, as del-icio-us. But the popularity of the tag does not always reflect its importance and representativeness for the resource to which it is associated. Starting from the assumptions that the same tag for a resource can take different meanings for different users, and a tag from a knowledgeable user would be more important than a tag from a novice user, we propose an approach for weighting resource’s tags based on user profile. For this we define a user model for his integration in the tag weight calculation and a formula for this calculation, based on three factors namely the user, the degree of approximation between his interest centers and the resource field, expertise and personal assessment for tags associated to the resource. A resource descriptor containing the best tags is created.